Remarkable development of computers and network techniques in these days has enabled vigorous provision of various information from information server apparatuses to client terminal apparatuses. Typical example is the information provider service using an information server apparatus such as an FTP (File Transfer Protocol) server or a WEB server on the Internet. Information (contents) is placed in such servers, and a client terminal apparatus designates an URL (Universal Resource Locator) of the information. Thus, the information designated by the URL is provided to the client terminal apparatus.
Different from a system distributing information on schedule as in the case of television (hereinafter simply denoted by TV) broadcast, generally, distribution of such information takes place independent of time. That the information is distributed independent of time means that the contents of the information to be provided cannot be changed with time. There exists, however, a demand for changing with time the contents of information to be distributed.
Japanese Patent Laying-Open No. 2002-207656 proposes an information server apparatus as a solution to such a problem. In the information server apparatus disclosed in Japanese Patent Laying-Open No. 2002-207656, when there are requests for getting information designating one same URL made from a plurality of web browsers through the network, the URL is switched in accordance with the times of arrivals of the requests at the information server apparatus. Pieces of information reflecting the corresponding times are placed at the URLs, so that different pieces of information can be distributed to the web browsers in accordance with the time when the requests from these web browsers are received by the server.
A method of providing information that coordinates network-based services with on-schedule, broadcast-based services is disclosed in Japanese Patent Laying-Open No. 9-223084. In the client terminal apparatus in accordance with the technique disclosed in this laid-open application, URLs of the network-based service are registered channel-by-channel in the similar manner as reception frequencies of the broadcast-based service. The client terminal apparatus is provided with a remote controller having a plurality of keys. A user selects a channel through an operation of the keys on the remote controller. When the selected channel is allocated to a TV broadcast, the client terminal apparatus displays the TV broadcast using a TV tuner. When the selected channel is allocated to a URL, the client terminal apparatus accesses to the URL through the network and displays the information.
In the information server apparatus disclosed in Japanese Patent Laying-Open No. 2002-207656, the URLs to be allocated to the users are determined in accordance with time of arrival of the user requests. Therefore, when there is a delay in arrival caused by a network delay, different URLs may possibly be allocated to two users who accessed exactly at the same time. Further, assuming that the information sever apparatus allocates a specific URL to a specific time and a user transmits a request past the specific time, allocation is impossible as the URL is already a thing of the past. Therefore, the information of the specific URL is not available to the user.
Further, the information server apparatus processes requests in the order of arrival. By this approach, when a request made by a user who accessed first but experiences a larger network delay arrives later than a request made by a user who accessed later but experiences a smaller network delay, the URL is allocated with priority to the latter. In other words, it is difficult to process the access requests fairly in the order of time when the users made access requests.
In the information server apparatus described in Japanese Patent Laying-Open No. 2002-207656, allocation of URLs is determined in accordance with the time of arrival of user requests. As a result, when the time of arrival is the same, connection to the same URL is always established. In actual operation, however, there may be cases where provision of different pieces of information is desired in view of the state of accesses from clients, even when the time of arrival is the same. The technique described in Japanese Patent Laying-Open No. 2002-207656 is not flexible enough to handle such a situation.
According to the technique described in Japanese Patent Laying-Open No. 2002-207656, it is impossible to see the information that was accessible in the past. However, one might wish to see now some information that was accessible in the past, or a user might be very much interested in the information that is being accessed and displayed at present and wish to make an access again later. In order to meet such requests by the users, a technique is necessary that can change the contents of information dependent not solely on the time of arrival. Such a technique is also desired to enable one enjoying information accessed at present to tell others of the address information (by, for example, e-mail).
For a user to access to some information, he/she must know a perfect address (such as the URL) to gain access to the information. Generally, an information server apparatus combines various pieces of information to form the information provided to the user. In order to enable a user to access to contents that will be formed in the future and changed with time, it is necessary to pass, time-to-time, appropriate addresses corresponding to the time of access to the client terminal apparatus. Consider a server that provides information associated with TV broadcast. It would be easily understood that various and many pieces of information would be provided time to time in one day.
It is difficult to manage these addresses on the side of the server or to pass these addresses down to the client terminal apparatuses.
As another approach, an information server apparatus may limit the number of users that can make accesses at one time. When users larger than the limited number make access to the information server apparatus, it is desirable to provide information from a different information server apparatus to the users accessed after the limited number has been attained. Further, when a plurality of users make access to the information server apparatus almost simultaneously with the limited number almost reached, it is desired that the user who started access earlier can connect to the information server apparatus with priority.
According to the technique referenced in Japanese Patent Laying-Open No. 9-223084, a user allocates keys of a remote controller to web services related to programs broadcast on broadcast channels, so as to be able to receive web services associated with the broadcast program. The keys allocated to broadcast channels and the keys allocated to specific web sites, however, are separate and not related to each other. Therefore, when a user wishes to receive a web service related to a broadcast program, he or she must consider by himself/herself the relation between the broadcast channel and the key allocated to the web service.
Recently, terminals such as portable telephones having functions comparable to those of common client terminals but limited resources because of size have come to be used. It is preferred that the services described above are readily available using such terminals.